Air feeding system for coal burners



AIR FEEDING SYSTEM FOR COAL BURNERS Filed 0G13. 5, 1930 Patented June 6, 1933 UNTE STATS ieiaessf j* NP ANTENNT oFFigcE y winniaivi w. aineiinv, or "sYnAcUsn, New `vom:

are riiiinine eYs'riei-i non eoAL summits Application Xled October 3, 1930. Serial No. 486,157.

`This invention relates to an air feeding system for coal and other solid fuel burners ascommonly usedin furnaces and boilers foi heatingpurposesl and is particularly useful fin` the distillation ofthe gases fiom the cheaper `grades of anthracite and bituminous coal andin the complete combustion of the distillation; i i

l Iii The main object isto provide simple and etlicient means adapted to be easily and quickly installed in oldor new furnaces or boilers for effecting a more rapid and coin plete combustion of the fuel and thereby to render such combustion substantially smokeless.` i i i One of the specific objects is to support the air distributing head within the combustion 4chamber in such manner that 'the inflowing air will be pre-heated and evenly distributed `inifan-like jets over and upon Athe surface ofthe fuehassuring a more complete and expeditious combustion of the gases immediately following the distillation thereof and 'i thereby to reduce to a minimum theismole content in. the products of combustion escaping througli'the chimney or other flue.

` In other wor( e I `have sought to concentrate and directthe iniiowing air from the exterior to thevsurface of the burning fuel through. substantially closed conduits passing from the underside. upwardly through y the fuel `for predieating and pressure pur-V y poses, and to distribute the heated air evenly over thesurfaceof the fuel for accelerating `and maintaining the combustion of the lib-` erated gases. i i

Another object is to provide simple and efficient means for concentrating and directing additional atmospheric air from the eX- terior throughthe fuel at different levels so as to accelerate the distillation of the gases j from the coal.

` Afuither object is `to provide simple and eilicient means forconcentrating and directing the inflow of external air from the un-v derside upwardly through the fuel grates i and fuel thereon forfurther accelerating the distillation of `the gasesfrom the fuelfV i z Another objectl is to provide ineans7 pref# gases immediately following theerably in the form of a fan orblower, pro jecting external air through the several conduitsinto `and above the surface of the fuel for additionally accelerating the `1 complete combustion ofthe fuel` and gases. i

Other objects and uses relatingfto specific parts of the apparatus will be brought ontin the foilowingdescription.` In the drawing V Figure l is a vertical sectional view ofa 6U portion `of a heater and fuel grate, together with my improved `air carbureting system, partlyfin elevation. j j i l j `Figures 2 and 3 are perspective views of the two plates forming the head ortop of 65 the carburetor system.

Figure is a perspective view of the air distributing element located below the fuelgrate. j

Figure `5 the heat refractory tubes surrounding the adjacent portion of the main upright air tube within the body of fuel in the combustion chambcr.` l

may be installed in any furnace or boiler MA- having a combustion chamber -aaiid an ash pit "or lower chamber -a.-`- underlying the fuel grate .B- and coni-` prising a main upright airtube #fl-- eX- 80 .Y

tending through a central opening b in the grate *B above the level of thefuel `Thevlower end of'r the central upright air:

conduit 1 is provided with a lateral eX- 85 tension -2-` leading to the exterior ofthe y heater Aw through an opening a} for connection:with an `extern al blower -`3-1 or equivalent means for` circulating the airV from the `outside of the heater, upwardly 9U is a perspectiveview of one of 70 .This air feeding and distributing system 75 rlhat is. the conduit -1- extends some distance through and above the grate B- to about the level of the surface of a predetermined quantity of fuel therein, so that the distributing head -4- will be disposed in a horizontal plane closely adjacent said surface.

The distributing head -4- is preferably composed of a pair of similar cup-shaped sections 4V- and -4- of considerably greater diameter than that of the upright tube 1- and arranged with their open sides facing each other, as shown in Figure l, the meeting edges of said sections being provided with a series of, in this instance three, relatively shallow bosses -6 projecting slightly beyond the remaining portions of the meeting edges of the sections to form the `circumferential slots 5 when the sections are resting one upon the other.

The lower section -4-, is provided with a central opening -7- communicating with the upper end of the pipe #1- and is also provided with a pendant hub -8- teleseopically supported upon the upper end of said pipe to permit the entire distributing` head to be easily and quickly removed by upward displacement, or replaced at will.

The top of the upper section -4- is closed and is provided with a series of, in this instance three, threaded apertures 9 for receiving a corresponding number of adjusting screws 10- which engage the lower section` -4- and serve as a means for adjusting the upper section relatively to the lower section for varying the vertical depth of the slots v-5-- as may be required to regulate the volume of air discharging therethrough, over the surface of the fuel.

It is now clear that when the heater is in operation, atmospheric air may flow from the outside of the heater, aided by the blow` er -3- if necessary, through the pipe -2- and thence upwardly through the vertical extension -lof the pipe -2 and thence upwardly through said pipe into the distributing head -4- from which it emerges through the radial slots -5- in all directions directly over the surface of the fuel.

During the transit of the air through the pipe '-1- the air becomes pre-heated and enters the distributing head -4- in this pre-heated condition where it is additionally heated and allowed to discharge through 'the slots -5- across the surface of the fuel to cause complete combustion of the gases which are liberated by the distillation of the coal and thereby to reduce to a minimum the smoke content of the escaping products of combustion.

The opening ibin the grate -B- through which the pipe -1- passes is of appreciably greater diameter than the external diameter of the pipe toallow the passage of air from the underside of the'grate or ash box -a through said opening to the overlying combustion chamber.

The grate --B- also permits the flow of air from the underside upwardly therethrough into the combustion chamber to additionally support the combustion of the fuel therein.

As previously stated, the pipe -1- extends some distance above the grate -B to the overlying distributing head *4.- and the intervening space between the distributing head and top of the grate is utilized to receive a plurality of, in this instance three. tubular sections -11- of heat refracting material such as lire brick, said sections being arranged one above the other around the adjacent portion of the air pipe -1- to extend from the top of the grate B- to approximately the underside of the distributing head -4- as shown in Figure l.

The interior diameter of each section -l1- is somewhat greater than the external diameter of the pipe -lto form intervening air passages --12-c communieating with each other and with the opening b through the center of the grat-c.

The opposite ends of each section l1- are provided with radial grooves or air passages -lextending from the air passages l2- to the exterior thereof to allow the air to'pass from the air passages -1Q- into t-he combustion chamber.

That is, the air from the blower -3- is free to pass upwardly through the openings -band passages l2- in the sections -l1 and thence through the radial passages linto the combustion chamber for distribution through the fuel at different levels, thereby assisting in supporting the combustion of suoli fuel and resultant distillation of the gas therefrom.

The lower horizontal extension 2- and lower end of the upright pipe -lare enclosed in a secondary air pipe 14rof greater interior diameter than the exterior diameter of the pipe l and its extensionv -2- to form an intervening air passage -l5-.

This pipe section -14- extends laterally through the opening a-in the heater shell A- and is preferably connected to the blower -3-, the inner upright end of the pipe 14ebeing connected to a supplemental air distributing head -16- having a central opening -17- communicating with the passage -l5.

The distributing head -l6- is supported upon the inner upper end of the pipe -14- just below the grate -B- and is provided with a plurality of, in this instance four, radially projecting branch pipes -l8- communicating with the interior of the head 16- and their outer ends closed by suitable plugs -l9-, the upper sides of said ure 1.

pipes -18 being provided with perforations 2(l* to allow the air to escape upwardly therefrom and thence into the co1nbustion chamber through the openings in the grate, as shown in Figure l.

If desired, the top wall of the supplemental distributing head -16 may be prog combustion chamber at different levels to assist in thecombustion of the fuel and resultant distillationof the gas therefrom.

As y illustrated the supplemental head -16- is suspended from the lower grate bar of the grate through the medium of suitablehangers -22-, shown in Fig- If desired, the upper inner end of the pipe 414- may be supported against down-- ward movement by means of a pin --23-n extending diametrically through registering openingsin the adjacent portions of the head the concentric spaced relation ofthe ad]acent portions of the pipes .-1- and `1 Y The outlet of the blower w3- is shown as provided with a damper *Q4- for regu lating the amount of air delivered to the wing heads 411- and 1G- and to the fuel The uppergrate section -b-- is rotatable relatively tothe underlying portions of the grate and is provided with a hub extending downwardly through registering openings in the overlying grate sections, said hub havings its lower end provided with a crank arm -2 adapted to be connected in any suitable manner to an external operating member for operating the grate section sired, without in any way disturbing the stationarypositions of the pipes land,

14E- and distributingv heads -4- and -16.

Operation "air in the ash pit is then in a more or less cold condition its upward movement through the fuel for draft purposes is more or less sluggish and,`in fact, this sluggish condition obtains over all conditions of' the lire in thel combustion chamber so that whenv the cheaper grades of coal, such as bituminous coal dust and anthracite buckwheat, is used, the natural draft from the ash `pit through the `fuel is insufficienti-to properly `support theconibustion of the fuel. i. y."

I am aware that when this quality of fuelis burned inthe usual heater, it has `been necessary touse motor-driven fans or equiv` alent devices for forcing the air fromV the ash pit upwardly through the` grates and thence through the fuel, but owing to the large volume of air usually `present in the ash pits` ofV thev ordinary heaters it is neces` sary touse a correspondinglylarge blower and a motor of `suiiicient power t'o drivethe same, but by concentrating the, volume of orly directing itinto andupon the surface ofthe fuel in the combustion `chamber -as in niypresent air distributingsystem,I ani' unable to use a blower of extremely small size and a driving motor of correspondingly small power and for obtainingbettercorn-` bustion than would be possible under'the ordinary blower system. y u In fact, afterthe fuel has been sufficiently ignited to produce the desired distillation of the gases the blower may be "disconnected andthe air allowed to flow freely Vfrom the outside throughthe pipe -1- and into the upper distributing head Llthereby causing the air to be preheated in transit and to be forcibly ejected through the thin slots -5- andacross practically the entire surface of theA fuel under its own expansive force, thereby causing` a complete .combus` tion of the gases immediately upon their appearance at the surface of the fuel afterdistillation, resulting in a blue blaze of high temperature extendingover theentire area escaping products Vof combustion` It has been found thatthe arrangement ofthe tubular sections -8-.- of fire brick or equivalent heat refracting material around the portion of the pipe 1 between` the grate -b and distributing head J1--v causes said sections -to become more or less incandescent when the fire is underway, thereby increasing the temperature of the air passing upwardly through the pipe 1f-y;

into` the distributing head ---t--` and inci-l dentally producing a more rapid and efficient combustion of all the gases at the surface of the fuel immediately upon their distillation;

. Furthermore, it` hasjbeen found that the combustion of the fuel is acceleratedbythef lateral distribution of the air from the in! terior of thesections --8- into the fuel at different levels and that this influxof air f into the interior of the sections -11- is materially aided by the connection of the air supply pipe 14- thereto, particularly i neurosisY under the pressure produced by the blower -3-.

It is now obvious that this complete combustion of the fuel and gases produces a 5 maximum temperature in the combustion chamber and incidentally induces a more rapid escape of the smokeless products of combustion through the chimney or Hue to v assist the draft even though the flue may be unduly restricted in area from any cause.

What I claim is:- l. An air feeding system for coal-burning heaters havingV a combustion chamber and an underlying air chamber, a fuel-supaorting grate, an air feed pipe extending fromr the underside upwardly through and. some distance above the grate, a distributor head mounted vupon the upper end of the pipe and provided with an air chamber for receiving air from the pipe, said head having air exit openings leading from the chamber to the exterior of the head, and a tubular enclosure surrounding a portion of the pipe between the grate and distributing head in radially spaced relation thereto to form an intervening air chamber communieating with the combustion chamber and with the first named air chamber. p 2. In an air feeding system for coal-burning heaters having a fuel-supporting grate provided With'a central vertical opening therethrough, said system including a hollow distributing head supported some dis- A `tance above the grate co-axial with said openi'ng and provided with'v an air inlet opening in its underside and exit openings in its peripheral walls, an air conduit connected to the inlet opening of the distributing head and extended downwardly therefrom 40 through the opening in the grate, and means for circulating air from the exterior of the heater through said conduit and-distributing head, a tubular member surrounding the porv tion of the conduit between the distributing head and grate in spaced relation to said conduit to form an air passage therethrough 'communicating Withj the opening in the grate, and means for conducting air from the exterior of the kheater to the opening in 450 the grate for ycirculation through said open-k ing into the tubular member.

3. An air feeding system for coal burning heaters having a grate, an air pipe extend-J l ing from the underside upwardly through and above the grate, an air distributing head mounted on the upper end of the pipe, an additional air supply pipe surrounding the portion of the first named pipe below the v grate and provided with an air'distributing 00 head underlying the grate.

In witness whereof I have hereunto set my hand this 30th day of September, 1980.

WILLIAM W. RIDGELY. 

